Vinyl chloride and vinylidene chloride polymers are known to be self-extinguishing and relatively more flame retardant than other polymers such as polyethylene, polypropylene, and the like. However, a substantial amount of smoke may be produced upon exposure of vinyl chloride and vinylidene chloride polymers to a flame. The fact that an additive is a flame retardant does not necessarily mean that it will have good smoke retardant properties, as is well known to those skilled in the art.
U.S. Pat. Nos. 3,821,151, 3,845,001, 3,870,679 and 3,903,028 teach use of certain copper, iron and/or molybdenum compounds as smoke retardants in PVC. U.S. Pat. No. 3,900,441 discloses mixtures of certain zinc and molybdenum compounds as smoke depressants in PVC. New smoke retardant vinyl chloride and vinylidene chloride polymer compositions are desired.